Almost all conventional residential homes, condominiums, and apartments have water supply systems that provide both hot and cold running water to the resident or a guest. FIG. 1 shows a simplified diagram of a residential water system 10 in which all supplied water 14 is provided to the residence through a water line 12, such as from a public water station or a private well. A portion 16 of the supplied water 14 flows along a cold water supply line 18 to be accessed by a user via a cold water faucet 20. The remaining portion 22 of the supplied water 14 is usually diverted to a hot water tank 24 to be heated and made available to the user via a hot water supply line 26 and a hot water faucet 28.
It has been known in the art that it is common practice for a resident of the average household to run, and thus discard, unheated water present in the hot water supply line 26 until the unheated water has been purged and the hot water from the hot water tank 24 is available at the hot water faucet 28 or at a shower head, for example. As the discarded water is sent down a drain, this otherwise clean and useful water is essentially wasted. Over a period of time, the clean water that is thus discarded may amount to many hundreds of gallons of water per annum per household. Moreover, the user may continue to run the water when not being needed, such as during lathering or shampooing, so as to maintain the hot water supply at a sufficient warm temperature at the hot water faucet 28.
To date, there have not been satisfactory methods to conserve such wasted water. Many conscientious residents collect the water in a bucket, for example, for later use in watering plants, or for pouring into a clothes washing machine. However, this requires extra physical effort, and cannot possibly conserve all the water that is run and not used while bringing hot water to the faucet or shower head. From a practical standpoint, most residents will not concern themselves with the wastefulness of sending clean water down the drain, as the living standards in most developed countries have conditioned people to use resources as necessary without regard to conservation practices, and there is a lack of understanding of basic scientific and environmental principles among the general population.